1. Field of the Invention
This invention relates to a dual flame method and apparatus for performing flame ion mass spectrometry.
2. Description of the Prior Art
In general the clogging of the orifice of a mass spectrometer sampling cone by SiO.sub.2 particles is a relatively novel problem about which little is written. However, concentric gas flows are, of course, well known in other arts and in the technical literature. There also are techniques known in the prior art for analyzing materials in concentric gas flows.
For example, U.S. Pat. No. 3,208,333 issued to Gilbert discloses a method for operating an atomizer burner for spectro-chemical measurement. The burner provides free concentric gas flows about a sample conduit. The inner gas flow provides the aspirating and atomizing action and the outer gas flow functions as a sheet separating the flame and surrounding atmosphere.
U.S. Pat. No. 3,141,741 issued to Hoele et al and U.S. Pat. No. 3,740,154 issued to Green disclose burners for use in analytical procedures where coaxially disposed tubes and ducts separately supply a burner kit with sample and flame gases respectively.
U.S. Pat. No. 3,879,126 issued to DeLew and U.S. Pat. Nos. 3,955,914 and 3,917,405 issued to Hartmann et al teach a flame photometric detection technique in which the sample to be analyzed is delivered to the tip of the burner separately from the combustion gases so that the sample is burned at the peripheral region of the flame.
U.S. Pat. No. 4,097,239 issued to Patterson discloses a two-flame burner for use in flame photometric detection in which a sample is burned in a first flame and the combustion products are subsequently combusted in a spacially separated second flame.